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> Interesting load development outcomes
Interesting load development outcomes
@ 10:03 am (GMT) |
David HartleyTwo new loads to develop, both using ADI AR2206H. I have a question that comes at the end of the post... first the data:Range conditions: about 18 deg C with a medium variable wind blowing from behind at about 05h30 to 11h30 if you imagine the target sitting at 12h00. Load #1 - varmint load Cartridge: ADI twice fired brass, CCI primer, Nosler Varmageddon 55gr (17240), OAL 2.260" (0.02" off the lands) Powder weights tested: 25gr, 25.5gr, 26gr AR2206H Rifle: Tikka T3 Supervarmint in .223, 1:12" twist Have owned this rifle for 4 years now and it's the most accurate I've ever had. Photos of load tests at 100m below: 
Pretty happy with that. The third load (26gr) is the max load in the ADI load data book. Load #2 Cartridge: Lapua brand new brass, Federal primer, Sierra Gameking 100gr SPBT (1560), OAL 2.640" (0.01" off the lands (see note below)) Powder weights tested: 31gr, 31.5gr, 32gr, 32.5gr, 33gr AR2206H Rifle: Howa 1500 in .243 with 20" barrel, 1:10" twist *Note* The COAL measured with the Hornady tool is 2.650" which is the same as the stated length for most of the 100gr hunting bullets (Sierra, Nosler, Hornady is 2.630"). This seems a bit short to me. This means there's little room to seat the bullet deeper to pull it off the lands, without potentially affecting pressures. This rifle is new. I broke in the barrel and zeroed the scope using Berger match bullets, mid range loads also using AR2206H, and was reasonably happy with the results. Photos of subsequent load tests at 100m below: 
So, finally to the question. The first shot with 31gr was with a dead cold barrel and it was way off. Like, WTF??? Assumed shooter error and continued. Subsequent shots up to the end of the 31.5gr group were spaced about 2 minutes apart and the barrel was only ever mildly warm. Then there's a fair gap in time to the start of the 32gr group, about 15-20 minutes, and the barrel is cold again. First shot - way off. Then another three shots, with a 2 minute gap between shots and a mildly warm barrel, this yields reasonable grouping for 32gr which might just scrape 1 MOA at 100yds. First shot of the 32gr group unlikely to be shooter error this time, exactly the same stance, wind, etc as before. Subsequent groups (32.5gr, 33gr) follow with 2 minute gaps, and a mildly warm barrel. Reasonable, but not great groups. So I'm a bit confused. Not had this before, usually groups with my hunting loads are pretty good, 1 to 1.5MOA. This new .243 hunting load is only 'marginally stable' according to the Berger stability calculator, but there's no sign of keyholing and I've never had problems with this length/weight bullet in .243 before. The soft points on these Gamekings are pretty variable. COAL is up and down by a fair bit, some of the soft points are a bit out of shape. But, with the exception the the two 'cold barrel' shots, the groups demonstrate that my medium game sized target is shot in the vitals and likely very dead, every time. I need to eliminate these outlier shots. Where to start? Can it be related to the apparently short maximum COAL of 2.650"? Any advice would be much appreciated. I am a first time poster on this forum, not normally one for posting stuff, but believe me when I say that there probably isn't a paragraph on Nathan's website that I don't know off by heart! Thanks Nathan. |
Replies
@ 03:35 pm (GMT) |
Bryan WebsterRe: Interesting load development outcomesThis is possibly the result of your 1:10 twist rifling and the use of 100 grain bullets. Years ago I had a Sako Forester heavy barrelled .243 that hated any bullets heavier than 95 grain. It shot like yours as shown.I switched to the Sierra HPBT 85 grain and got one hole groups. For coyotes and wolves I used 55 grain bullets to save on pelt damage and it shot those well too. I recently ordered a benchmark barrel and a new action for a .243 build and as I wanted to shoot the newer heavy .243 bullets (105 grains and up) I asked the barrel maker for his advice and he said a 1:8 twist would work well but above 107 grain bullets a 1:7 twist would be best. I hope this is some help for you. I would just back off to the Sierra 85 gr hpbt and try it. I shot many deer with that bullet with no issues |
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@ 07:55 pm (GMT) |
David HartleyRe: Interesting load development outcomesThanks BrianThe bullets I used to break in the barrel were 100gr, and there's very little difference in the length, which is what affects stability I believe. So its a maybe at this stage? I'm going to test some 75gr VMax later. I realised that got the orientation wrong on one of the photos cos I had turned the target box 90deg at one point. Now I realise that both 'outlier' shots were an almost identical height higher than the rest of the group. So not so random after all. Maybe shooter error... the bipod / rear bag combo. 
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@ 03:09 am (GMT) |
David HartleyRe: Interesting load development outcomesToday's load development yielded a very satifying outcome. The red bullseye is 40mm diameter. This thread hasn't generated a lot of interest but it's maybe worth sharing the outcome as several suggestions from elsewhere and here said it was the bullet weight and 1 in 10" twist rate, a common concern with .243. But I've shot 100gr Sierras for years in a .243 T3 with the same twist and had ok groups.On another forum someone suggested load density (fill ratio) as a starting point, so I switched to a slower burning powder (ADI AR2209) and upped the weight. Load: 40gr ADI AR2209, C.O.A.L. 2.645", Sierra Gameking 100gr BT Spitzer. This C.O.A.L. is a soft touch on the lands, no neck crimp. 
I was pissed off to the max with shot #5, which I pulled left with poor exhale / squeeze timing. Here's an interesting photo of what happens with slightly different values for the powder weight and the C.O.A.L.: Load: 39gr ADI AR2209, C.O.A.L. 2.625", Sierra Gameking 100gr BT Spitzer. This C.O.A.L. is 0.020" back from the lands. 
I started at 38gr and was a bit over it after the 39.5 gr group, thinking it was just gonna be a case of poor stabilisation after all. But then at 40gr, suddenly the group tightened up, repeated it after the barrel cooled, and job done. So there's a sweet spot for sure, and that's where I'll stick. For this rifle, it's a 90% fill ratio and just touching the lands. Anything else is a non-starter. |
@ 04:15 am (GMT) |
Jonathan KittermanRe: Interesting load development outcomesDo you have or know anyone with the Sierra flat base version 1540 to try out.What other bullet or bullets did you try out in this weight? What has been done with the rifle and have you gone through it per Nathan's books? I checked Sierra reloading manual #5 and their test rifle was 9 1/8 twist. |
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@ 05:22 am (GMT) |
David HartleyRe: Interesting load development outcomesSorry there's an error in the earlier post - the second photo showing poor grouping was 41gr AR2209, not 39gr, i.e. more powder than the best grouping, not less. Also, I should have mentioned that the first photo with the 40gr tight grouping is the second group shot with this load, following a scope adjustment to improve the zero. |
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@ 05:54 am (GMT) |
David HartleyRe: Interesting load development outcomesQuote: Do you have or know anyone with the Sierra flat base version 1540 to try out.
What other bullet or bullets did you try out in this weight? What has been done with the rifle and have you gone through it per Nathan's books? I checked Sierra reloading manual #5 and their test rifle was 9 1/8 twist. Jonathan, I don't have any of the ProHunter 1540 flat bases, but I've got several hundred Gameking 1560 boat tails, so pretty keen to work up a load that makes good use of them... I made up a list of all the commonly available hunting bullets in the 85-100gr range and ran their dimensions through the Berger stability calculator and whilst it says the Gameking is marginally stable, its done well for me in the past in a Tikka .243 with 1 in 10" twist, so I was pretty keen to find a way to make them work in the Howa before I just assumed it was a stability problem. When I first shot the rifle to break in the barrel, I used two bullets - 75gr Hornady VMax and 100gr flat base Speers, an old bullet that I think has been discontinued. The VMax delivered very tight groups with AR2206H. The flat base 100gr bullets were ok but not great. I wasn't too fussed at the time because I was just using a mid-velocity load to be kind to the barrel, no tuning for accuracy at the time. The rifle is as bought new, no mods. It has the 20" barrel. No I have not been through it as per Nathans books because I don't have the books. Maybe I should. As you know the bullet manufacturers differ slightly with their .243 twist rates in their load data. You are right that Sierra is 9 1/8 which is the Remington 700 twist for .243. Hornady, Nosler, VihtaVuori, Barnes and ADI use 1 in 10" in their manuals. But Ruger American .243s are 1 in 9"... The only consistent thing I've been able to find is that they all state their 105gr+ pills require a faster twist, e.g. 1 in 8. I havent found a bullet manufacturer that states that their 100gr bullets will not work with a 1 in 10" twist, other than Berger andtheir VLDs which are too long for the Howa chamber. |
@ 08:15 am (GMT) |
Jon ShortRe: Interesting load development outcomesHi David,Not sure if it helps but my brother shoots a 223 Howa 1500 (ss barrel & action in walnut stock, bedded by me with Nathan's kit & 2 stage trigger lightened etc) & his pet load is; 60G Hornady Varmint projectiles OACL with 20 thou or 0.5mm jump at 58.04mm 26G AR2206H. (V slightly compressed) Clover leaf Groups. Very accurate & lethal on Fallow Deer. Wind affects this calibre quite a lot even at 100yds. I'll check the twist rate & come back to you but I think it's 1 in 9 maybe 10. Nosler Partitions of same weight we could not get to work / group consistently no matter what we did which was a shame as it's a tougher bullet. Cheers, Jon |
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@ 08:18 am (GMT) |
Jon ShortRe: Interesting load development outcomesSorry my mistake, just saw you Howa is 243 not 223 like your Tikka.Please ignore my comments. Cheers, Jon |
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@ 08:47 am (GMT) |
Jonathan KittermanRe: Interesting load development outcomesSome rifles just prefer the flat base over the boat tail or the other way around. It was just if you had them available to try.[b] |
@ 10:05 am (GMT) |
Mike DavisRe: Interesting load development outcomesIm not a huge fan of the EBRG/twoforfree but if any I owned shot that badly it would get sold off or binned pronto.your .223 group prooves you can shoot,so the nut behind the butt may not be the issue. mates .243 will put any and all loads in tiny groups of less than inch all day long and without exception every one Ive seen will do pretty darn well. first off...... #1 will rifle still do same as it did before with other loads???? (if not check scope etc etc etc) #2 you seem to have the answer to your question,the speer flat base would possibly be shorter so maybe the suggestions made above have merit. #3 overall length wont matter as the oglive will be the same and distance to rifling will be the same (check out box of sierra hpbt if you want to see large variation) |
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@ 02:15 pm (GMT) |
Bryan WebsterRe: Interesting load development outcomesMike's comments are spot on. I checked my old records for the .243 I used to have and it sot boat tail bullets by far the best - grouped like the .223 targets above. |
@ 08:34 pm (GMT) |
Bob MavinRe: Interesting load development outcomesI use 100gn Sierra Game King in 1:10" twist shooting 1/2 MOA groups out to 300m |
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@ 08:44 pm (GMT) |
Bryan WebsterRe: Interesting load development outcomesMy younger son has a Weatherby Vanguard S2 in .243. It has a 1:10 twist and we loaded up some 100 gr GameKing bullets but found with several different powders it would get groups no smaller than 1 moa, yet the 85 grain HPBT Sierras shoot into 1/2 to 3/4 moa. It is to me always interesting to do load workups for new rifles like this yet see other people having decent performance in the same brand of rifle with the 100 gr Game Kings that his rifle does not like as much. Not terrible out to 200 yards with them so functional anyway.I supposed a long time back that some of my rifles were like dogs I have had and preferred to eat what they wanted. |
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@ 10:20 pm (GMT) |
David HartleyRe: Interesting load development outcomesAll good, thanks for the comments.It's probably got the same problem with stability at the 100gr boat tail length & weight threshold, same as many other rifles in this calibre & twist, regardless of brand or pricepoint. Some will shoot them ok, some won't. I read heaps on it and got some advice elsewhere about burn rates, fill ratio, soft seating on the lands, and hey presto it worked for me. It's shooting acceptable groups with the 100gr BTs if I do may part (which I didn't on the last shot of the one in the photo, as I said I screwed it up). The group in the photo is 13/16" or 20mm, not counting the one I pulled left, which isn't too bad on a windy Waikato day. So throwing out the rifle? That might be a bit of an overreaction... I'm using a comparator on my calipers to check seating depth and I marked the dummy rounds with ink to see when they touched the lands and I'm happy with that. The only other ammo I've used for accuracy / scope setup is the Hornady V-Max in 75gr and it makes one hole with those. I don't have any more of the 100gr flat bases left so I've ordered some Pro Hunters as per Jonathan's advice, I think thats a good way to go. We'll see what happens. This Howa is a cheap but proven rifle with a 20" barrel for woodland and farmland use. The shorter barrel and Hogue stock is a big plus in the ute, on the quad, in the bush... overall the rifle is a much much better product than the Ruger American, Savage or Mossburg competition at this price point IMO. It'll be used mostly on pest goats, but we have deer on our boundary and its bloody windy here, when we go looking for deer we can normally get within 150m for a dependable shot. I can't support using .243 here to shoot larger deer than smaller / yearling hinds at over 200m, and only out to that range if I am 100% convinced the testing has delivered the confidence to put the shot in the vitals with the right kind of projectile. If they don't drop and make it back over the fence and down towards the river, it's nigh on impossible to find them. If there's any doubt, use the .308 and 165gr pill or don't take the shot at all. I'm signing off on this one now, thanks again for the comments. Off to fill the freezer up the Ruatiti... |
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@ 11:52 am (GMT) |
David HartleyRe: Interesting load development outcomesA postscript...Some minor tweaks to the load has resulted in a reliable 0.5MOA groups at 100yds. Switched to Sierra ProHunter 1540 flat bases as per suggestion above. Projectile seating depth is set to a soft touch on the lands. The Lapua cases are now fire formed with a neck resize only. After seating, a moderate neck crimp. The first two photos show the first ProHunter group shot before the scope was re-zeroed, the scope eye relief having been changed to better suit the wife, plus addition of suppressor. We're shooting off the back of the ute, standing, using a bipod with a small rear Cardwell bag supporting the grip. The target squares are 0.5": 
After setting the zero, me and the wife did some more "real" timed groups, by hopping out of the vehicle, quickly setting up the rifle on the bonnet (bipod only, no bag support on the grip) and shooting a quick three shot group. Thus mimicking what we do in the field when culling goats or coming across a pig or deer. Both shooters delivered reliable 1.0MOA - 1.5MOA groups at 100yds on a windy day, with just the bipod, a hot rifle and a minimum of time (few seconds): 
The ProHunter 1540 load is more accurate in this rifle than the Gameking 1560s, if you are thinking in benchrest terms, but the animal on the receiving end of either pill isn't going to know the difference. The stability calculators deliver a 'stable' outcome (just) for the ProHunter (SG = 1.51), and a 'marginally stable' outcome for the GameKing (SG = 1.36). Bottom line is that the lower BC / shorter OAL ProHunter is a more stable pill in the 1:10" twist barrel at the 100gr weight... for this rifle. Whether stability is influencing accuracy that much is an unknown, compared to say fill ratio or shooter discipline. Nothing has been done to the rifle other than the addition of a DPT over barrel suppressor. So that's the end of the story. This budget Howa 1500 with the Hogue stock has delivered outstanding performance once we worked out the loads, with a bit of help... At the 100gr weight, cheap Federal factory ammo was very average, then low fill ratio hand loads with my normal powder were rubbish. A switch to a slower burning powder and a high fill ratio showed promise but there was still some work to do around exact powder weights, seating depths and then case prep and crimping. Also there's been a lot of work on our shooting positions, in particular the amount of downward force applied by the left hand to the forend just behind the bipod. I think bipod "bounce" has potentially played quite a big role in perceived inaccuracy early on, especially shooting off the ute and experiencing the odd flier. Now our work is on longer range tests out to 500yds to learn the Weaver scope EBX reticle. |
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@ 01:14 pm (GMT) |
David HartleyRe: Interesting load development outcomesJust a quick follow up on the Howa 1500 in .243.Did some 300m testing yesterday with a couple of mates, in quite tricky conditions. This to prep for a hare hunt from a very handy shooting position with a wide field of view over a fallow scrubby hill paddock that's full of critters, typical range 275-325m. Blustery wind ~20kmh average at the shooting position blowing at -100° (L-R) dropping to nil wind from about 150m to the target. Used Strelock+ to help with elevation adjustments and dialed in the recommended clicks on the Weaver GrandSlam 4-16x44 scope. Wouldn't normally do this, would hold over instead with this scope of course, but thought it would be interesting to see how it went. First test was 75gr VMax, 46.3gr AR2209. 3 sighter shots to test the wind assumptions (Strelock+ wanted -3MOA, I settled on 2.25.) Then followed up with a 4 shot group: 
Then switched to the Sierra 100gr ProHunters, 40.0gr AR2209, no sighter shots, just a quick 3 shot group: 
Pic of the shooting position, target circled. 
The VMax returned a 4.1cm group at 300m. The ProHunter returned a 7.5cm group just using the Strelock+ assumptions. So that's basically MOA at a bit over 300yds. Not too bad for a cheap 2-for-the-price-of-1 $800 light contour hunting rifle with a flexible stock, eh... I guess my point is that I shoot with a couple of blokes with a $2800 Sako and a $3000 Kimber in .243 both with Zeiss glass and neither rifle will better the Howa performance, the Sako will equal it, just, the Kimber not quite. And its not the shooter that's the difference, we all deliver pretty much exactly the same results with the same rifle. Then we went varminting and took 12 hares at an average range of ~300m, hardly any wind. The Howa got 9 from 10 shots with VMax. The Sako got 2 from 4 shots, also with VMax, and Kimber managed a measly 1 in 5 shots with 70gr Sierra BlitzKing. We all missed with the Kimber and agreed there's something not quite right with it. Fair to say that there was some head scratching over a couple of beers last night. Real world out-of-the-box performance outcomes of the upper mid-range brands vs. budget rifle aren't justifying the dollars was the conclusion. These two critters weren't concerned by any of this though, as all they could be bothered about was recovering after the hare hunt. They didn't catch any. They never do. But that's not the point, is it? 
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